Lycoming Engines is a major American manufacturer of aircraft engines. With a factory in Williamsport, Pennsylvania, Lycoming produces a line of horizontally opposed, air-cooled, four-, six- and eight-cylinder engines including the only FAA-certified aerobatic and helicopter piston engines on the market. The company has built more than 325,000 piston aircraft engines and powers more than half the world's general aviation fleet, both rotary and fixed wing. Lycoming is an operating division of Avco Corporation, itself a subsidiary of Textron.

Lycoming claims to have been founded in 1845 by "Madame Ellen Curtis Demorest". However, the early history of the company especially prior to 1860 is unclear. In New York, New York, between 1860 and 1887, the Demorests published fashion magazines and operated the Demorest Fashion and Sewing-Machine Company producing "Madame Demorest" and "Bartlett & Demorest" sewing machines and selling Ellen Demorest's innovative paper patterns for dressmaking. During this period, Ellen Demorest patented several fashion accessories, while her husband patented improvements to sewing machines and an apparatus for the vulcanization of rubber.

Around 1883, Gerrit S. Scofield & Frank M. Scofield bought the Demorest brand and the sewing machine business, and constructed a factory in Williamsport, Pennsylvania (in Lycoming County). At the urging of the newly established Williamsport Board of Trade, citizens invested US$100, 000 in the new manufacturing facility, which employed 250 people. The factory produced 50 to 60 sewing machines per day, and the company sold them for between US$19.50 and US$55.00 each. With the development of the "New York Bicycle" in 1891, the company diversified its product offerings. Until the early 1900s, the factory produced sewing machines, bicycles, typewriters, opera chairs and other products.

By 1907, the manufacture of sewing machines had become unprofitable for Demorest, and the company was sold and restructured as the Lycoming Foundry and Machine Company, shifting its focus toward automobile engine manufacture. In 1910, the company supplied its first automobile engine to Velie, and during the early post World War I era, the company was a major supplier to Auburn.

Velie

By 1920, Lycoming was producing 60,000 engines a year, with a 2,000-strong workforce. To handle the capacity, a new foundry complex was built in Williamsport that year. Eventually Lycoming became Auburn's principal supplier, and in 1927 Errett Lobban Cord bought the company, placing it under his Auburn Manufacturing umbrella group. Among the engines Lycoming produced for Cord was an L-head straight-eight engine of 7.8 l displacement that produced 125 horsepower. This was used in the Cord L-29. Lycoming also produced a double overhead cam straight 8 used in the legendary Duesenberg J series. This powerplant produced 265 horsepower, six times the power of a contemporary Model A Ford. A supercharged version, generating 325 horsepower, was installed in the Duesenberg SJ and SSJ models.

Cord L-29

Duesenberg SJJ

In 1929, Lycoming produced its first aviation engine, the nine-cylinder R-680 radial. This was a fairly successful design, and was used widely in light aircraft, including Cord's Travel Air.

R-680

In the 1930s, Lycoming made a number of attempts to develop successful high-power aircraft engines. The 1 200 hp O-1230 was Lycoming's attempt to produce an engine based on the United States Army Air Corps hyper engine concept, and used a variety of features to produce nearly 1 hp/in3 (46 kW/L) of engine displacement.

O-1230

However, by the O-1230's entry into service, it had been surpassed by other designs and the US$500 000 investment was not recouped. Another attempt was made to rescue the design by stacking two O-1230s to make the 2 300 hp H engine H-2470 but the only design to use it, the Vultee XP-54, never entered production. The Curtiss XF14C was originally intended to be powered by the H-2470, but the engine's poor performance led to the adoption of an alternative radial engine on the prototype, the XF14C did not enter production.

Curtiss XF14C

Undeterred by the O-1230/H-2470's failure, Lycoming turned to an even larger design, the 36-cylinder XR-7755, the largest aviation piston engine ever built. This design also experienced problems, and was only ready for use at the very end of World War II, when the aviation world was turning to turbojets and turboprop engines to power future large aircraft. There was apparently some interest in using it on the Convair B-36 Peacemaker bomber, but the 28-cylinder Pratt & Whitney R-4360 Wasp Major four-bank radial was used instead.

Convair B-36 Peacemaker

Through the 1920s and -30s, Lycoming had still been supplying automotive manufacturers with engines. However, these clients each slowly went out of business or switched to Continental engines for their vehicles. By 1931, the company was supplying automotive engines to only three companies: Auburn, Cord and Duesenburg, still all under the control of Cord. These companies closed their doors in 1937, after which Lycoming switched to exclusively designing and producing engines for aviation.

In 1939 Cord re-organized all of his aviation holdings into the AVCO group, at which point the engine manufacturing company became "AVCO Lycoming". They also leased the government-owned Stratford Army Engine Plant in Stratford, Connecticut and produced Wright radials under license. After the war, this plant was converted to produce the T53 turboshaft engine, one of their more successful designs. From this point on the piston and turbine engine lines remained separate, with the piston lines being built in the original Williamsport factories, and turbines in Stratford.

T53 Turboshaft

By 1961, Lycoming produced 600 to 700 engines per month. Their most successful post-war products were a series of air-cooled flat-4 and flat-6 general aviation engines. Most famous among these are the O-235 and O-360 four-cylinder engines, and the O-540 six-cylinder engine. Many light aircraft are powered by versions of these engines, with power ratings in the 100–360 hp range. Engines in this series also include the O-320 four-, O-580 six- and O-720 eight-cylinder engines, and the advanced turbocharged and fuel-injected 450 hp TIGO-541 variant of the venerable normally aspirated O-540.

TIGO-541

In the early 1980s, the general aviation market suddenly diminished and Lycoming's piston engine business was significantly impacted. Attempts were made to move some of the turbine production to Williamsport, but this led to a series of quality control problems and eventually it was abandoned.

Another attempt to rescue Williamsport was made in introducing the "radical" SCORE engine, a Wankel engine originally developed in a partnership between Curtiss-Wright and John Deere. Curtiss-Wright lost interest in the design just as it was maturing and sold it to Deere, who brought in Lycoming to sell into the aviation markets. They were guaranteed a startup run by Cessna, also owned by Textron. Just as production was ready to start, Cessna announced they were halting their small-aircraft business for an indefinite period, and SCORE was cancelled. The remains of the Deere licenses were later purchased by Rotary Power International, which briefly produced a 340 hp version.

Textron purchased the company in 1985. In 1994, Textron sold the Lycoming Turbine Engine Division, located in Stratford, Connecticut to AlliedSignal, who merged it with the Garrett Engine Division of AlliedSignal as part of AlliedSignal Aerospace, later becoming part of Honeywell Aerospace in 1999.

In the early 1970s a new player arrived on the aviation scene in the USA, Vans RV aircraft are designed to use Lycoming aircraft engines, this development made a massive contribution to the ultimate success of Lycoming Engines

The RV-4 and RV-6/6A use 150/160 hp 0-320 or 180 hp 0-360 engines.

RV-4

The RV-7/7A and RV-8/8A can accommodate O-320, O-360 or angle valve IO-360 (200 hp) engines.

RV-7's and RV-8's

The RV-9/9A is suitable for Lycoming engines in the 118 hp to 160 hp range.

RV-9

The engine used in the 4-place RV-10 is the Lycoming IO-540D4A5 rated at 260 hp. Van's recommendation for the 4 place includes any of the parallel valve 540's which are available from 235hp on up to the 260hp version.

RV-10

These engines are the most readily available, affordable, and reliable of the possible choices. Other aircraft engines of similar configuration, weight and power might possibly be used, but only the Lycoming will fit the mounts and cowls supplied with the kits.